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By Virgil A. Marple

The objective of this contract was to conduct characterization, evaluation and/or calibration studies of instrumentation used for measuring the quantity of respirable dust in mining atmospheres. Initially, this work involved the upgrading and detailed evaluation of the aerosol test chamber and the development of impactors with respirable classification characteristics. These were used as standards in the chamber for measuring the quantity of respirable dust based on either the ACGIH or BMRC respirable dust criteria. A program was then conducted to calibrate several photometers. In addition, the mass sensitivity of the GCA RAM-1 photometer to water droplets in the respirable size range was determined. Three additional studies were also made in this program. First, an experimental study was performed to ascertain the effect of crosswind, cyclone orientation and particle size on particle sampling and penetration through the 10 mm Dorr-Oliver cyclone. Second, a theoretical study was conducted to refine the theory used to predict the particle collection characteristics of impactors. Third, filter samples with known quantities of diesel and coal particles were produced and delivered to the B. of Mines for testing a Raman scattering analysis technique to discriminate diesel particles in the presence of coal dust.

Jan 1, 1984

By McHenry Mosier

This paper describing mining practice at Morenci, Ariz., is one of a series of articles on mining method, and practice in the various mining districts in the United States. At present (1929) practically all the mineral production in the Morenci district is from the Humboldt mine of the Morenci Branch, Phelps Dodge Corporation. The mining method used is adapted to the type of ore body being exploited; it has been developed by adopting methods used elsewhere and making necessary changes to fit local conditions. Improvements in current practices are still being made.

Jan 1, 1929

By Donald W. Mitchell

Research shows that water neutralizes the explosion hazard of coal dust when present in sufficient quantity and when intimately mixed with the dust. The quantity of water required to neutralize coal dust and coal-rock dust mixtures is about equal to the limiting moisture adsorptive capacity of the dust; the adsorptive capacity increases with increase in the fineness and volatile content of the coal. Pools of water or high atmospheric humidity do not reduce the explosion hazard. Although wetted dust is less dispersible than dry dust, poor dispersibility cannot be relied on as the sole safeguard against explosion. Dust mixtures that contain water in excess of their limiting adsorptive capacity are dispersed and ignited by severe initiation sources. Pure coal dust adsorbs water with difficulty and retains water poorly; adsorption and retention is increased by the addition of rock dust the coal; the rock dust agglutinates wetted coal and assures that incombustible is present should drying occur. Therefore, it is advantageous to rock-dust wet areas in bituminous coal and lignite mines. When coal-rock dust mixtures are wetted and subsequently dried, the explosion hazard is about the same as for dust which was not wetted.

Jan 1, 1962

By A. G. Galaitsis

This report summarizes the work performed under the USBM Contract No. J0245001. The purpose of this work was to expand and improve the scope and accuracy of the method developed under USBM Contract No. J0113056 for the prediction of the number of overexposed workers in the mining industry. A significant portion of the noise data were acquired during mine visits-that took place in the-course of this contract. These data were obtained with time-resolved dosimeters which among other things store a time history of the sampled noise for an eight hour work period. The remainder of the noise data have been obtained from MSHA files and from other BoM-sponsored projects. The report reviews the prediction model, discusses the model's assumptions and approximations, describes the function of the developed software, offers typical examples on the use of the software and includes plots of the newly acquired noise data records.

Jan 1, 1986

By James J. Dowd

During and immediately following World War II, the heavy demands for steel required the mining of unusually large quantities of coal for the manufacture of metallurgical coke. The largest demand for metallurgical coke is in the Appalachian region, which comprises central and western Pennsylvania, Maryland, West Virginia, Virginia, eastern Kentucky, Tennessee, and Alabama. This demand is satisfied by coke made from coals within the region; consequently, the reserves of coking coal in this region are being depleted more rapidly than reserves in other coal-producing regions. The supply A' high-quality coking coal during the war was inadequate, and some coke were forced to use inferior coals. The coke produced from these inferior coals adversely affected the rate of production. Another national emergency probably would produce a similar condition, and in the interest of -national security, the Munitions Board of the National Military Establishment requested the Bureau of Mines to evaluate the reserves of coals suitable for the manufacture of metallurgical coke. All bituminous coals in the Appalachian region are coking, and as the coal that produces the better metallurgical coke become depleted, other coal previously considered inferior will be used. The general trend is toward the use of lower-quality coals for metallurgical purposes.

Jan 1, 1950

By Eugene H. Skinner

The 7-mile Flathead Tunnel, located in the central Salish Mountains of northwestern Montana, was constructed between 1966 and 1969, With the contract awarded April 19, 1966, drill and blast tunnel excavation began September 30, 1966, and was completed June 21, 1968, in 488 tunnel-driving days, Peak advance was 66 feet per day. On June 27, 1969, all tunnel concrete lining was completed. Average wall and arch concrete placing rates exceeded 1,700 cubic yards daily, with nearly half of the concrete placed during a severe winter season. Major cost savings in concrete tunnel lining were achieved through a value engineering clause in the contract. Achieving consistent results and high rates of placement in concrete lining ranked equal to ground control in overall tunnel problems. Ground control problems exceeded expectations and were of continual concern throughout excavation, One support collapse in the tunnel and one portal slide condition developed during construction. Critical surface geologic exposures were largely obscured; only a portion could be accurately projected underground, An instrumentation program to gather basic data on rock defamation near the heading face for support purposes was a pioneering effort. The Flathead Tunnel was placed in service on November 7, 1970.

Jan 1, 1974

By Jürgen F. Brune, Liming Yuan, Alex C. Smith

To provide insights and assistances for the optimization of ventilation systems for U. S. under-ground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study is being conducted to investigate the effect of the ventilation scheme on the prevention of spontaneous combustion in longwall gob areas. This report focuses on the flow patterns within the gob under three different ventilation systems; one-entry and two-entry bleederless systems as well as a three-entry bleeder system. The gas flow in the caved gob area is simulated as a laminar flow through porous media while the gas flow in ventilation airways is simulated as a fully developed turbulent flow. The air flow patterns are visualized using flow path lines. Air velocity contours and vector data are also obtained. The possible location of critical velocity zones where the gob is most liable to spontaneous heating is discussed.

By Kenneth O. Bayard, John D. Sullivan

"This repot continues the series of papers being prepared at the Southwest Experiment Station of the Bureau of Mines in cooperation with the department of mining and metallurgy, University of Arizona, on factors involved in the leaching of ores. A list of previous publications is given in the bibliography at the end of this paper.Four factors are essential to the leaching of any copper-bearing ore: (1) A solution that will attack the copper minerals must get into the body of the ore particles; (2) the copper minerals must be dissolved by the solution; (3) the solution containing the dissolved copper must find its way out of the voids of the rocks into the main solution; and (4) the copper in solution must be recovered by some means of precipitation.This paper considers the third step -- the extraction of the water-soluble copper. From leached ores. The usual commercial practice in leaching copper ores consists of: (1) Crushing the ore to pass through a screen with approximately one-quarter or one-third inch openings; (2) charging the crushed ore into a fat; (3) adding, usually by upward percolation, a solution that will attack the copper minerals; and (4) washing the copper-laden solutions out of the ore with solutions weaker in copper than the pregnant solution, and finally with water. A countercurrent system of leaching and washing is usually employed. In some plants the solutions are circulated during leaching and washing, and in others they are not. In some plants the wash solutions are added by upward percolation, while at Chuquicamata the so-called ""piston-displacement"" method of washing is employed.The following condensed resume of the leaching cycle of the plant of the Inspiration Consolidated Copper Co. is given to present to the reader a picture of the steps involved in a typical leaching cycle. This plant was recently described in detail.4 The ore, crushed to pass openings 11/2 inches in diameter, passes over a screen with ¼-inch openings. The undersize from the screen goes to a Dorr howl classifier that removes the primary slime from the circuit. The overflow from the classifier is treated in a slime-leaching plant. The oversize of the ¼-inch screen passes through rolls, where it is crushed to pass a 3/8-inchscreen. The undersize from the 3/8-inch screen join with the coarse material from the classifier, and the combined products become the feed to the leaching vats. There are 13 concrete lead-lined leaching vats. The complete leaching cycle is 13 days. Eight tanks are under acid-iron content at all times; three are being washed, one tank is being filled, and the one is being excavated. The electrolyzed solution from the tank house, to which amount of new acid has been added, is put on the oldest tank of ore under need This solution travels from tank to tank and finally emerges from the newest ore"

Apr 1, 1931

By D. C. Fleck

Electrorefining yttrium from selected low-melting yttrium--base alloys is investigated, and various halide systems are studied as potential electrolytes for use in preparing low-oxygen yttrium by electrorefining unalloyed yttrium. Yttrium cathode products having significantly less metallic impurities than the anode materials were prepared from alloys containing nickel, iron, and manganese by electrorefining in LiCl-YC13 electrolytes at 900° to 1,000° C. Yttrium-copper and yttrium-magnesium alloys are not suitable as anode feed materials, An evaluation of chloride, fluoride, bromide, and mixed chloride-fluoride electrolytes showed that cathode products containing much less oxygen than the anode material can be obtained in the fluoride and mixed chloride-fluoride systems. Initial cathode current density has no apparent effect on the purity of the products obtained in both phases of the investigation.

Jan 1, 1973

The objective of this study was two-fold: 1. To perform a world literature search pertinent to the analysis, selection and design of hoisting systems and their components and to codify the search into a literature compendium. The search resulted in a technical data file of over 1500 hard copy items. The compendium index was also suitable for establishing a comprehensive computer-loaded data base on the subject. 2. To develop a comprehensive system of guidelines to cover salient aspects of analysis, selection and design of electrical, mechanical and structural components of a hoisting system with a view to establish parameters for maximum safety and efficiency of operation, installation and revision of the system. 3. (a) In-shaft equipment design and specification criteria are considered as they influence guideline preparation. (b) A comprehensive review of hoist electric drives and controls as applied to mine hoists is set forth with special reference to duty cycle calculations and their effect on electrical component selection.

Jan 1, 1988

By R. Q. Shotts

Factors of geological structure and occurrence of coalbeds, plus the resulting mining conditions, have required more care in preparing coals in Alabama than in most other districts almost since mining Alabama coals began. For this reason, literature on these coals may be interesting to those in areas where prime coals have been mined out, and thinner and less regular beds must now be exploited. This literature review has been arranged in order of subject matter. Some references have been listed more than once, but each separate review is limited to the material pertaining to the subject matter being discussed. For those seeking specific information, the authors have indicated which items repeat material and which items are most complete or specific. Geology, preparation, and carbonization of coal have been reviewed the most frequently.

Jan 1, 1963

By John H. Soulé

"Bureau of Mines engineers3/ examined the White Eagle fluorspar mine on September 3, 1943, and again on February 17, 1944. The examinations led to a proposal for the exploratory project upon which this report is based. The project, which was supervised by the author and P. L. Russell, was started on April 6, 1945, and completed on June 26, 1945.Geologists4/ of the Federal Geological Survey examined, mapped, and reported on this property prior to initiation of the Bureau of Mines project.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. H. S. Dean, assistant director.Special acknowledgment is due to C. H. Johnson, Rolla, Mo., Division, Mining Branch; to W. R. Storms, mining engineer in charge of the New Mexico field office; and to J. H. Hedges, chief of the Tucson, Ariz., Division Mining Branch. Acknowledgment is owed, also, to Robert Trace and Howard Rothrock, of the Federal Geological Survey, for help in mapping the surface and in logging drill cores.The White Eagle claim is in the east-central part of sec. 34, T. 19 S., R. 9 W., Cooks Peak Mining District, southeastern Grant County, New Mexico. The property is reached from Deming, N. Mex. by taking the paved U. S. Highway No. 260 northwestward for 13 miles to the junction with State Route 61. State Route 61 is a graded but unpaved road and is followed northward for 8 miles to a junction with a poor dirt road, which is followed eastward for 11 miles to the mine. Silver City, N. Hex., is about 50 miles northwest of the mine and may be reached by several routes.The White Eagle patented claim was owned by L. H. Duriez of Vanadium, N. Mex., W. D. and W. A. Howard of Deming, N. Mex., Alvan N. White of Silver City, N. hex, and: Mrs. E. M. Saunders of Los Angeles, Calif. D. P. McCabe of Lordsburg, N. Mex., a former lessee, has recently contracted to purchase the property.The White Eagle claim was located about 1920 and was patented in November 1933. It was leased to Cooper Shapley of Deming, N. Mex., in July 1933; to General Chemical Co. from August 1938 to May 1940; to Antonio Cristo from October 1940 to the fall of 1942; and f is ally it passed into the hands of D. F. McCabe of Lordsburg, N. Mex., in May 1945.Approximately 25,000 tons of fluorite ere containing about 65 percent CaF2, have been mined and shipped from this property.5/ Most of this ore was mined by Cooper Shapley and the General Chemical Co. and shipped to the General Chemical Co.'s La Purisima mill at Deming. No exact data on production are available."

Jul 1, 1946

By E. D. Calvert

This Bureau of Mines report discusses the electric-arc reduction of zirconium and hafnium oxides with carbon yielding a metal-metallic carbide mixture. The carbon to oxide ratio in the feed determines the metal to carbide ratio in the product. A sample of this product was produced -or testing as a feed for the deBoer iodide-dissociation process. A new technique for producing pure carbides is described, which uses the intense heat of the arc to volatilize the carbide. The condensed vapor form , crystals of nearly stoichiometric carbide, INTRODUCTION This research examines the preparation of refractory metal carbides in the controlled atmosphere electric-arc furnace.

Jan 1, 1962

By R. Q. Shotts

Factors of geological structure and occurrence of coalbeds, plus the resulting mining conditions, have required more care in preparing coals in Alabama than in most other districts almost since mining Alabama coals began. For this reason, literature on these coals may be interesting to those in areas where prime coals have been mined out, and thinner and less regular beds must now be exploited. This literature review has been arranged in order of subject matter. Some references have been listed more than once, but each separate review is limited to the material pertaining to the subject matter being discussed. For those seeking specific information, the authors have indicated which items repeat material and which items are most complete or specific. Geology, preparation, and carbonization of coal have been reviewed the most frequently.

Jan 1, 1963

By E. L. Garton

[AnalY3e s of Qany crude t) i 1 s prod.uced in Loui sia.na are incl udeo" in re!Jor~ ~ th'l t have b en u~li shed by the BurOllU 0: i?{ine s. The first rc-port,j} givin..; analyseG of 6 Louisiana crude oils, '-vas pUblluhed in 1921'l.s,nd this was 1'0110\ cd a year later by P.ep rt of InvBstign.tions 21a6t~ givi~ 7 addi tional analyses. The G7even :,ost il'!lportant of these analyses were incol"]lorated in Bulle~in 91,.2, is~ued in 1928. In 1934, analyses of 26 cl ... ude oils j)roduced in southern Louisiana ",ere published ? .§! The present report I)renonts analysos of 72 ad(~itional samples of crude oil frorl 4-, fields in 23 "l)ari shefl in Loui f",io.r]

Jan 1, 1939

By Victor E. Kral

"INTRODUCTION The Segerstorm-Heizer property was examined by engineers 3/ of the Bureau of Mines in May and June 1942 and Mach 1943. As a result of these examination, the Nevada State Department of Highways,constructed 9.3 miles of graveled road under the mine access-road program. A magnetometer survey was made by the Geophysical Division 4/ in October 1943, and as a result the Mining Branch set up and conducted a core-drilling,project. Work on the deposit started May 24, 1944, and was suspended on July 31, 1944, but was resumed on December 4, 1944 and continued until completion on March 27, 1945.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as it, primary objective the more effective resource to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploration work, and prepares the final report. The Metallurgical Branch, R. G. Kinickerbocker, chief analyses samples and performs beneficiation tests."

Mar 1, 1947

By J. R. Thoenen

This circular is part 6 of the third paper (entitled "Excavation") of a series summarizing the technical problems involved in the production and preparation of sand and gravel. Part 1 discussed the use of power shovels, draglines, and excavator cranes; part 2, power scrapers, slackline cableway excavators, and hydraulic monitors; part 3, hydraulic, clamshall, ladder, and diaper dredges; part 4, haulage equipment, particularly industrial cars with locomotive or hoist as the motive power; part 5, conveyor belt, motor truck, pump and pipe line, towboat and barges, and aerial-trams haulage. This circular discusses the application of these various types of equipment to the different types of sand and gravel deposits and contains a reference bibliography. It completes the discussion of excavating problems.

Jan 1, 1936

By A. B. Campbell

The mines in the eastern part of the now active region of the Tri-State zinc district of Missouri, Kansas, and Oklahoma have unusually acid water, which during periods of moderate or no rainfall is used in the mills to replace losses from evaporation, seepage-, and tailings disposal. Its use has caused difficulties by corrosion of equipment and by interference with flotation. The growing importance of flotation, which requires good water, and the increasing troubles caused by the corrosion of the milling equipment have prompted the Mississippi Valley Experiment Station of the United States Bureau of Mines, in cooperation With the Missouri School of Mines and Metallurgy, Rolla, Mo., to investigate the action of the waters on flotation and to undertake to develop means of obviating their harmful effects. The work was under the immediate direction of W. T. Schrenk, consulting chemist, United States Bureau of Mines, and professor of chemistry Missouri School of Mines and Metallurgy, and. Will H. Coghill., supervising engineer of the ore dressing section of the United States Bureau of Mines.

Jan 1, 1932

By Serge Rudchenko

A study to determine the potential use of retaining structures in open pit backfilling. Research and review of the open pit mine environment, mine waste disposal, and past and current use of retaining structures. A development of specific structures, the culvert/ tunnel concept, and an anchor block retaining concept. The cost benefit of retaining structures used for in-pit backfilled waste.

Jan 1, 1981

By J. S. Miller

The Bureau of Mines conducted surface tests to determine the feasibility of using liquid explosives for underground rock fracturing. The effects of configuration, confinement, length, critical layer thickness, and fracture-propping sand on detonation and explosive propagation velocity of desensitized nitroglycerin were studied, using polymethyl methacrylate and glass-plate reservoirs through lengths from 3 to 12 ft, with explosive-layer thicknesses from 0.1875 to 0.0312 in and in aluminum tubes 8 ft long with diameters from 2.000 to 0.125 in. Interval and continuous detonation velocity data were obtained. Under the test conditions detonation velocity was dependent upon explosive confinement and fracture-propping sand. The detonation velocity of a confined nitroglycerin explosion in aluminum tubes can be reduced by as much as 85 percent, when the tube contains fracture-propping sand. The shape of the reservoir, whether triangular or rectangular, has little effect on the detonation velocity or explosive propagation. The critical or minimum explosive-layer thickness between glass plates, capable of supporting propagation, was 0.0312 in. The presence of a fracture-propping sand in the sheetlike layers increased the critical explosive layer thickness to 0.0625 in. In nitroglycerin-filled and nitroglycerin-sand filled tubes, the minimum tube diameters successfully tested were 0.125 in and 0.375 in, respectively.

Jan 1, 1969